5,854 research outputs found
Topological superconductivity at the edge of transition metal dichalcogenides
Time-reversal breaking topological superconductors are new states of matter
which can support Majorana zero modes at the edge. In this paper, we propose a
new realization of one-dimensional topological superconductivity and Majorana
zero modes. The proposed system consists of a monolayer of transition metal
dichalcogenides MX2 (M=Mo, W; X=S, Se) on top of a superconducting substrate.
Based on first-principles calculations, we show that a zigzag edge of the
monolayer MX2 terminated by metal atom M has edge states with strong spin-orbit
coupling and spontaneous magnetization. By proximity coupling with a
superconducting substrate, topological superconductivity can be induced at such
an edge. We propose NbS2 as a natural choice of substrate, and estimate the
proximity induced superconducting gap based on first-principles calculation and
low energy effective model. As an experimental consequence of our theory, we
predict that Majorana zero modes can be detected at the 120 degree corner of a
MX2 flake in proximity with a superconducting substrate
Full counting statistics of renormalized dynamics in open quantum transport system
The internal dynamics of a double quantum dot system is renormalized due to
coupling respectively with transport electrodes and a dissipative heat bath.
Their essential differences are identified unambiguously in the context of full
counting statistics. The electrode coupling caused level detuning
renormalization gives rise to a fast-to-slow transport mechanism, which is not
resolved at all in the average current, but revealed uniquely by pronounced
super-Poissonian shot noise and skewness. The heat bath coupling introduces an
interdot coupling renormalization, which results in asymmetric Fano factor and
an intriguing change of line shape in the skewness.Comment: 9 pages, 5 figure
Self-Learning Determinantal Quantum Monte Carlo Method
Self-learning Monte Carlo method [arXiv:1610.03137, 1611.09364] is a powerful
general-purpose numerical method recently introduced to simulate many-body
systems. In this work, we implement this method in the framework of
determinantal quantum Monte Carlo simulation of interacting fermion systems.
Guided by a self-learned bosonic effective action, our method uses a cumulative
update [arXiv:1611.09364] algorithm to sample auxiliary field configurations
quickly and efficiently. We demonstrate that self-learning determinantal Monte
Carlo method can reduce the auto-correlation time to as short as one near a
critical point, leading to -fold speedup. This enables to
simulate interacting fermion system on a lattice for the first
time, and obtain critical exponents with high accuracy.Comment: 5 pages, 4 figure
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